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SNOW Jeffery g Won Treadwell&Rollo San Joaquin County Environmental Division 23 December 2003 Page 2 AGE advanced 8 borings (B-1 through B-8) and obtained groundwater samples from each boring (Figure 1). The water samples were analyzed for total petroleum hydrocarbons as gasoline (TPH-g) and as diesel (TPH-d) and volatile organic compounds (VOCs). Nothing was detected in any of the water samples except from the sample collected from boring B-3. The groundwater sample contained TPH-g, TPH-d, ethyl benzene and xylenes at concentrations of 17,000, 12,000, 1,300 and 2,090 ug/1 micrograms per liter(ug/1)respectively. PROPOSED SOIL AND GROUNDWATER INVESTIGATION The intentions of the proposed soil and groundwater investigation are to identify the source and extent of the identified groundwater impacts located down gradient of the Carando Site at boring B-3. In order to identify the source and delineate the extent, six borings are being proposed. Soil and groundwater sample locations were selected for the following rationale: Boring CSB-1 is located upgradient of AGE boring B-3,between the Carando Site and the adjacent 424 North Madison Street Site to help determine if the identified groundwater impacts may originate from offsite. Two borings, CSB-2 and CSB-3, will be located down gradient of the previous gas station pump location. These locations will further delineate the extent of the previously identified groundwater impacts. Boring CSB-4 will be located upgradient of the previous gas station pump location, but down gradient of the former service station. The boring will help determine if the previous service station building may be a source of the identified groundwater impacts. Two borings, CSB-5 and CSB-6, will be located in the estimated location of the previous gas station pumps. The borings will help determine if the gas station pumps are a source of the identified groundwater impacts. Continuous soil cores and groundwater samples will be collected from each boring. Samples will be collected using a direct push method with a cased hole. Six groundwater samples will be collected from the cased borehole. The borings will extend to approximately 25 feet below ground surface (bgs)to obtain soil and groundwater samples. Inunediately after collection, samples will be labeled, and placed in an iced cooler. All groundwater samples and selected soil samples will be submitted to a California state certified laboratory for analysis using chain of custody protocols. All samples submitted for analyses will be analyzed for TPH-g and volatile organic compounds (VOCs) using EPA Method 8260, and TPH-d using EPA Method 8015 Modified.